From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36008C433E1 for ; Fri, 21 Aug 2020 20:19:45 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D590020735 for ; Fri, 21 Aug 2020 20:19:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="njkQpcRW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D590020735 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4BYCYC0xJSzDq7F for ; Sat, 22 Aug 2020 06:19:43 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux-foundation.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=akpm@linux-foundation.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=njkQpcRW; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4BYCSJ3v4qzDrHn for ; Sat, 22 Aug 2020 06:15:28 +1000 (AEST) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9477A20735; Fri, 21 Aug 2020 20:07:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598040478; bh=ignXh6GswzXrZuZocSxHHQfCSn5EcPz6JCZGg+djnYo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=njkQpcRWmyvRGvq8Ez91V2VkE1Zs62ocapcA2kFZe6Cg3jHjvrg/HHMBFU7llUhLq pibH5nQ/+1y7fY2Rj6xKk66sjW7+05COtWLKo7FT9ik+mMR+lneY17JFnOY5rRvOSo 4E2SVYhlV9OdHOnpvUTpJrFSRWD0cVpJMF1873g0= Date: Fri, 21 Aug 2020 13:07:57 -0700 From: Andrew Morton To: Nicholas Piggin Subject: Re: [PATCH v6 01/12] mm/vmalloc: fix vmalloc_to_page for huge vmap mappings Message-Id: <20200821130757.289570e4bb491672087d3396@linux-foundation.org> In-Reply-To: <20200821151216.1005117-2-npiggin@gmail.com> References: <20200821151216.1005117-1-npiggin@gmail.com> <20200821151216.1005117-2-npiggin@gmail.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , linux-mm@kvack.org, Zefan Li , Jonathan Cameron , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Sat, 22 Aug 2020 01:12:05 +1000 Nicholas Piggin wrote: > vmalloc_to_page returns NULL for addresses mapped by larger pages[*]. > Whether or not a vmap is huge depends on the architecture details, > alignments, boot options, etc., which the caller can not be expected > to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page. I assume this doesn't matter in current mainline? If wrong, then what are the user-visible effects and why no cc:stable? > This change teaches vmalloc_to_page about larger pages, and returns > the struct page that corresponds to the offset within the large page. > This makes the API agnostic to mapping implementation details.